Fact checking self test myths

Fact checking self test myths

Wednesday 2nd June 2021
Dr John Rees

Are self test kits regulated in the UK? What about false positive and negative results? Dr John Rees fact checks the myths around self testing kits. Dr Rees has a PhD from St Bartholomew's Hospital, University of London and is a Eurostars technical expert, with over 30 years experience in the development of laboratory and point of care medical diagnostics.


Traditional established healthcare pathways are best
This is TRUE. Discussing your health concerns with your doctor is best. Nevertheless, self test kits are easily accessible, easy to use, give reliable results and can help prompt you to have that conversation with your doctor about your health concerns when you may otherwise might not have.

Self test kits are not regulated in the UK
FALSE. In the UK, self test kits are more tightly regulated than tests used in hospital laboratories.

Self tests are difficult to use
This is FALSE. All self tests legally available in the UK have to undergo user trials with laypersons to show that the majority of people can use the tests easily. These trials are independently reviewed by a Notified Body of scientists and clinicians to ensure compliance with UK and EU regulations. Even if you have used a similar test kit before, or are a health care professional, ALWAYS read the instructions through completely before touching the components. Then read them again. If you are still unsure, then contact the manufacturer before starting.

Some self test kits are not accurate
This is TRUE. Some self test kits can be bought online that are not certified for use in the UK. Buying your self test kits from a known retailer or pharmacy is the safest way to ensure that the tests you are using meet the necessary regulations. Confusingly, a test advertised as 'professional' means that it does not meet the regulatory standards required for use by laypersons! Every component within a self test will have been independently reviewed to check that they are fit for purpose before the test kit can be certified as meeting UK and EU regulations. As well as the test device itself, most of the components will also be regulated and certified medical devices themselves including lancets, swabs, pipettes - even the sticking plaster!

Self tests give false positive and false negative results
This is TRUE, but is also applies to hospital laboratory tests as well. All doctors are aware that all medical tests whether performed in the lab or at home will give a small number of false positive or false negative result. Hospital laboratory test results can also vary from one lab to another, even when using exactly the same test, from the same manufacturer.

Self tests can cause unnecessary worry
This may well be TRUE in some circumstances. However, a simple self test result can also help give peace of mind or prompt the user to visit the GP. The chemistry used in self tests is generally the same as that used in laboratory tests so a positive result in a self test will, except on very rare occasions, give exactly the same result in a hospital laboratory test but must be taken in context of your symptoms. Speak with your doctor.

Widespread use of self tests will increase the burden on GPs
FALSE. If you are concerned enough to buy a self test kit then perhaps you should consider speaking with your doctor or pharmacist anyway? Nevertheless, a self test result could allow your doctor to make a more informed diagnosis or referral during your consultation. Take the instruction leaflet with you during your appointment so that they can see the type of test that you have used but always respect the decision of your GP. A blood test result is just one of many factors that your doctor will use to make a diagnosis.

Only a doctor can diagnose a medical condition
TRUE. Doctors take into account many factors, not just the result of a single blood test from your hospital, but also your clinical history as well. A result from a self test is there to prompt you to speak with your doctor about your health concerns - sooner than you might have.

I've heard that self tests often give 'invalid' results
FALSE. Due to the way in which medical devices are manufactured and quality controlled, the chances of a self test failing and giving an invalid result is very remote. Usually, invalid results are due to unwittingly misinterpreting the instructions. Some self test devices will have a built in 'fuse' so that an invalid result rather than a wrong result will be given if the instructions have been misinterpreted, for example, not enough/ too much blood or diluent. Although it can be frustrating to get an invalid result it does help prevent the user acting on an incorrect result. Medical device manufacturers will have highly qualified scientists and technical staff who will be pleased to help.

Self tests aren't proper medical tests
FALSE. Medical self test kits are usually manufactured by divisions of well known multi-national pharmaceutical companies or by medical device diagnostic or biotech companies with expertise in the development and manufacture of laboratory diagnostics as well. For instance, the actual self test device itself is also likely to be used in hospital laboratories or clinics as well!

SELFCheck is a range of CE certified self test kits for a wide range of health concerns, assembled in the UK in ISO13485 certified laboratories and are widely available from major retailers including Lloyds Pharmacy, Superdrug and Well Pharmacy. For further information please see